Macroscopically expanded, three-dimensional, apertured polymeric webs are generally known in the art. As used herein, the term "macroscopically expanded", when used to describe three-dimensional plastic webs, ribbons and films, refers to webs, ribbons and films which have been caused to conform to the surface of a three-dimensional forming structure so that both surfaces thereof exhibit the three-dimensional pattern of the forming structure, the pattern being readily visible to the naked eye when the perpendicular distance between the viewer's eye and the plane of the web is about 12 inches. By way of contrast, the term "planar", when used herein to describe plastic webs, ribbons and films, refers to the overall condition of the web, ribbon or film when viewed by the naked eye on a macroscopic scale. In this context "planar" webs, ribbons and films may include webs, ribbons and films having fine-scale surface aberrations on one or both sides, said surface aberrations not being readily visible to the naked eye when the perpendicular distance between the viewer's eye and the plane of the web is about 12 inches or greater.
Examples of macroscopically expanded, three-dimensional, apertured plastic webs which are particularly well suited for use as a topsheet in absorbent articles are disclosed in commonly assigned U.S. Pat. No. 3,929,135 issued to Thompson on Dec. 30, 1975; and in commonly assigned U.S. Pat. No. 4,342,314 issued to Radel et al. on Aug. 3, 1982. Said patents being hereby incorporated herein by reference.
A prior art process for producing macroscopically expanded, three-dimensional, apertured plastic webs is disclosed in commonly assigned U.S. Pat. No. 4,609,518 issued to Curro et al. on Sep. 2, 1986, which is hereby incorporated herein by reference. The patent to Curro et al. discloses a continuous, multi-phase process for debossing and perforating a substantially continuous web of substantially planar polymeric film to coincide with the image of one or more forming structures each having a patterned forming surface with a multiplicity of apertures. A fluid pressure differential is applied across the thickness of the web of film to cause the web of film to conform with the forming structure. While this process has been found to be particularly well suited for forming polymeric webs into various structures, application of the fluid pressure differential across the thickness of the web of film washes away surfactants within the film which are exposed to the fluid during the forming operation. Accordingly, when the formed webs are placed in their end use, i.e., as a topsheet in an absorbent article, such as a disposable diaper or sanitary napkin, they do not have the desired surface properties as the surfactant has been removed during the forming operation.
It is an object of the present invention to provide a process for producing surfactant treated formed polymeric webs where the material is of such a structure that the surfactant is not removed during the forming operation.
It is another object of the present invention to provide a process for producing a surfactant treated formed polymeric web wherein a fluid pressure differential is applied across the thickness of the film to cause the film to conform with a forming structure.